1. The X Factor
Defining the Concept of Experience
Stefano Bussolon(B)
Department of Psychology and Cognitive Science, University of Trento, Trento, Italy
stefano.bussolon@unitn.it
Abstract. The term User Experience has become mainstream. But
what is an experience? In this paper I will give a definition of the con-
cept, explaining it within the paradigm of evolutionary psychology. I will
briefly describe its main components (executive functions, episodic and
semantic memory), mechanisms (learning, reinforcement, evaluation),
and goals (the motivational system and the inclusive fitness). Finally,
I will provide some reasons of the usefulness of an explicit definition of
experience, both within an academic context and the design and business
practice.
We use our own experience and memory and wisdom and art Anaxagoras -
Fragment 21b.
1 Introduction
The term user experience is 30 years old [26]. It has an official definition (ISO
9241-210), and is gaining momentum: a growing number of professionals define
themselves as user experience designers, and the importance of the uxd is increas-
ingly recognized by the industry.
Nonetheless, the concept remains elusive: Hassenzahl [20] calls it an evasive
beast, Law et al. [27] gave five different definitions, the site All About UX cites
27 different user experience definitions.
Though some common elements recur, the concept seems more a family
resemblance than a core concept: ux is seen as a holistic, multidisciplinary app-
roach to design, where information architecture, interaction design, information
design, graphic design, usability, accessibility, content management converge to
the final product or service.
The concept of experience is usually only implicitly defined, and different
aspects of it are usually reported: the needs; the perceptions and responses of
the user to the product; how a person feels; the experiential, affective, meaningful
and valuable aspects; the result of motivated action; the past experiences and
the expectations; the interaction of internal states, a system, and a context; a
momentary, primarily evaluative feeling.
Even when explicit definitions of experience are proposed [13,16], the authors
are usually “not interested in experience per se but in experience in relation to
interactive products” [21].
c Springer International Publishing Switzerland 2016
A. Marcus (Ed.): DUXU 2016, Part I, LNCS 9746, pp. 15–24, 2016.
DOI: 10.1007/978-3-319-40409-7 2

2. 16 S. Bussolon
If, in the last 30 years, a formal definition of the x of ux is still not emerged, is
it really necessary? As a teacher in a course of human computer interaction I find
the lack of an explicit and comprehensive definition of the concept particularly
frustrating. Furthermore, I believe that a working conceptualization of experi-
ence could help the community to identify a shared methodology of research,
analysis, design and evaluation of a product or service.
2 The Definition of the Concept
The Oxford dictionary defines the noun experience as
– Practical contact with and observation of facts or events
– The knowledge or skill acquired by experience over a period of time, especially
that gained in a particular profession by someone at work
– An event or occurrence that leaves an impression on someone
The three meanings refer to 3 related but different things:
– the phenomenological experience of the conscious me-here-now
– the episodic memory of memorable experiences [28]
– the process of abstraction of a number of experiential episodes in a pat-
tern/scheme/script [37]
The first meaning represents what I’m experiencing right now, here. If I’m
mindless of what is happening, and if what is happening is nothing new (for
example, I’m reading a book while I’m commuting, and nothing unusual hap-
pens) this event will somehow reinforce my scheme of that kind of event (the
scheme of commuting) and I will forget the specific event [38]. If I’m living some-
thing new, or if something unexpected and worth noting happens, however, I will
remember the most salient events of the episode.
To identify the commonalities of the different meanings of the term experi-
ence, I propose a definition of the concept based on its main attributes.
In my definition, a prototypical experience is the subjective, conscious,
intentional representation of an episodic autobiographical event:
– it has a strong phenomenological grounding, and is lived as a non mediated,
immersive flow of consciousness;
– is usually triggered by a motivation
– can be imagined, and therefore mentally anticipated
– can be the result of a decisional process, a choice
– can be planned, at different levels of detail
– can be remembered
– is usually subject of evaluations: before, during and after
– can trigger a learning process
– can become a habit

3. The X Factor 17
The episodic and semantic memory and the executive functions are at the
basis of the experiences. From a phenomenological perspective, an experience is
a temporal window of the salient events that happened, are happening or are
expected or planned to happen. From the past, present or future experiences we
can build mental representations. Those representations integrate a causal and
motivational dimension (why), a temporal dimension (when), a spatial dimension
(where), and are formed by instances of conceptual classes (what) and possibly
other people (who).
Concepts are organized in semantic networks and in hierarchies (taxonomies).
The temporal, causal and spatial dimensions are hierarchically organized as well.
The causal dimension is organized in goals and task hierarchies.
3 An Evolutionary Perspective
To understand the role and the functions carried out by the experiences, it is
useful to adopt an evolutionary perspective [9]. The evolutionary psychology is
based on the assumption (shared with the evolutionary biology) that the purpose
of all living beings is their inclusive fitness [29].
In a complex environment, the inclusive fitness can be better achieved trough
the cultivation of a number of material and non material goods. An individ-
ual with good skills, a solid social network, living in a favorable environment
and owning some material goods has greater chances to maximize her inclu-
sive fitness. Following this reasoning, it is assumed that the basic needs (living
in a safe environment, physical and mental health, good relationships, mater-
ial and economic resources, autonomy, competence, identity, meaning [11,12,15]
are assets that increase the odds to maximize the inclusive fitness of the indi-
vidual [18,25]. Humans, therefore, evolved the drive to satisfy those basic needs,
because this enhanced their inclusive fitness. This hypothesis extends the results
of the use of an intrinsically motivated reinforcement learning system of an arti-
ficial agent [34].
Affective and cognitive functions are seen as adaptations: “mechanisms or
systems of properties crafted by natural selection to solve the specific problems
posed by the regularities of the physical, chemical, developmental, ecological,
demographic, social, and informational environments encountered by ancestral
populations during the course of a species’ or population’s evolution” [41].
The satisfaction of the basic needs becomes the ultimate goal [33]. The cog-
nitive an affective systems evolved to orient the individual to identify and ful-
fill both the ultimate and the proximate goals, to explore and to exploit the
environment.
3.1 Learning
Knowledge transforms information into decision making to increase the inclusive
fitness trough the satisfaction of the basic needs and proximate goals. Learning
is, in the evolutionary perspective, a form of adaptation.

4. 18 S. Bussolon
From the evolutionary perspective, the function of the learning mechanisms
is to improve the fitness, by mapping the environment and the behaviors that
decrease the risk of dangers and increase the odds to fulfill one’s needs.
Humans (and other animals) use two different strategies to learn to choose
actions that lead to positive and prevent negative outcomes [2]: model based
and model free (or value based). Model based strategies involve an internal
representation of the environment, whereas model free ones associate a behavior
within a context and it’s reward history [42].
The model-based mechanism consists in the ability of the agent (biological or
artificial) to build an internal, dynamic representation of a physical or conceptual
environment. The main advantage is that a journey within a model is much more
economical and less risk prone.
Some nodes and paths of the conceptual space have an affective valence,
because they represent dangers or aversive situations (negative valence) or the
satisfaction of goals, subgoals or basic needs (positive valence).
Trough the simulation it is possible to identify - and memorize - some paths;
this corresponds to the planning process. Every choice we make at any junction
corresponds to a decision making process.
The main disadvantage of this mechanism is that a systematic, brute force
exploration of the conceptual space is prone to a combinatorial explosion, and it
becomes necessary to employ some heuristics. The process of generalization of
experiences in schemas constitute the main heuristic: every time an individual
encounters a situation that is similar to a known pattern, she uses the schema
as the model, and tends to adopt those behavioral paths that correspond to
the past experiences [36] and reinforcements [7], therefore using the model-free
mechanism of habits as well [10].
3.2 Planning
Szpunar [39] define planning as a multicomponent process that operates at var-
ious levels of abstraction and serves as a predetermined course of action aimed
at achieving some goal. It involves defining a variety of goals and subgoals, pri-
oritizing those goals, monitoring one’s progress, and reevaluating the original
plan. Planning is the process of identification and memorization of a path in a
conceptual space. The process implies the identification of the goal and of the
possible routes. The representation is hierarchical: the main goal is subdivided in
subgoals, in a recursive way. The agent estimates the value of the main goal, the
cost of the tasks (in terms of resources, time, physical and psychological fatigue)
and their possible intrinsic value.
This metaphor is a spatial one: the navigation of a conceptual space, the iden-
tification of a path, the journey. What individuals plan is, however, a sequence
of behaviors and actions. [31] use the theater metaphor: the agent is a direc-
tor that images a plot, trough the recombination of episodic elements within
the structure of schemas and scripts (episodic simulation). Both the planning
and the evaluation assume the form of mental travels, away from the egocentric
me-here-now, in space, in time - toward the future for the planning, toward the

5. The X Factor 19
past for the evaluation of past or ongoing experiences - and in the mind of other
agents (theory of mind) [1,19,35].
The ability to simulate specific future events plays an important role in the
planning process. The constructive episodic simulation hypothesis contends that
episodic memory provides a source of details for (future) event simulations [1].
The constructive nature of episodic memory allows the flexible recombination of
such details into a coherent simulation.
Episodic simulation supports autobiographical planning, trough the coop-
eration between the episodic memory system, that provides the content, and
executive control processes, that allows the buffering and co-ordination of infor-
mation [4].
3.3 Executive Functions
Executive functions play a fundamental role in devising, implementing, updating
and evaluating plans and goal directed behaviors [5,14,22]. Inhibitory control,
working memory and cognitive flexibility are the three main components of the
executive functions. The working memory has the role to integrate temporally
separate units of perception, action, and cognition into a sequence toward a
goal [24], and to actively play with the representation. Inhibitory control allows
us to avoid the distraction of salient internal or external stimuli that are in
conflict with the plan and the goal. Cognitive flexibility allows to shift between
subgoals (for instance, when a task is over), to identify creative and innovative
ways to behave, and to adapt to unforeseen circumstances.
The dialog between executive functions, episodic and semantic memory allow
the agent to:
– identify and represent the goal, map the goal hierarchy
– identify the path: the sequence of actions to reach the goal, and the sub-goals
– keep the goal and the path in mind
– at any juncture, start the appropriate action
– inhibit the alternative actions and the cognitive processes that can interfere
– monitor the action and detect any significant mismatch between the plan and
the execution
– when required, update the plan; when opportune, modify the goal.
3.4 Evaluation
An important component of both learning mechanisms is the evaluation of the
outcome and of the process that lead to it: only what works is reinforced. The
evaluation, in the model-free mechanism, is mainly based on the dopaminergic
liking-wanting system. The evaluation process of the model-based system, on
the other hand, is much more complex, and is based on different mechanisms:
– the dopaminergic system, that is able to reinforce even the anticipation and
the simulation of the experience;

6. 20 S. Bussolon
– the cognitive evaluation of the process and the outcomes;
– the affective, emotional evaluation, both before, during and after the
experience.
The evaluation of an experience depends also on its motivations: when extrin-
sic, goal oriented, the evaluation is mainly cognitive; when intrinsic, experience
oriented, the evaluation is more emotional.
The Affective System. Within the perspective of evolutionary psychology,
the main functions of the affective system are focused on:
– affective forecasting: the emotional anticipation of a simulated experience [17]
– the orientation of the behavior [40]
– the emotional evaluation of an ongoing or past experience [32].
3.5 Motivations
From a motivational perspective, it is possible to differentiate intentional expe-
riences (those events we choose to live) and unintentional ones (events that
happens but are not the result of any sort of decision from the subject). Inten-
tional experiences can be differentiated between habits (model-free), goal ori-
ented (model-based) extrinsically motivated experiences, and intrinsically moti-
vated experiences. Among intrinsically motivated experiences, it could be useful
to differentiate hedonic and eudaimonic motives.
It is important to observe that such categories are not mutually exclusive.
Experiences are very often a mix of non intentional events, habits, goals and
intrinsic motivations. Image a lunch with your colleagues; the lunch is a habit
(every working day, at 1 pm, usually at the same restaurant), it is goal oriented
(eating some food), it has some hedonic (that delicious dessert) and some eudai-
monic aspects (spending time with the colleagues). If the restaurant is closed,
and you are forced to take something at the fast-food nearby, the experience has
an unintentional component.
In differentiating between hedonic and eudaimonic motives I will adopt the
distinction made by Huta and Ryan [23]: the main function of hedonia is the
self-regulation of emotions, and it’s effect is strongest at the immediate or short-
term time scale. The function of the eudaimonic motivated experiences is to
fulfill at least one of the basic human needs (relationship, competency, autonomy,
identity, self esteem, meaning). The two motivations tend to overlap (eudaimonic
experiences tend to be associated by positive affect and emotions).
4 The Functions of Experiences
Experiences play a central role in both model-free and model based systems.
The model-free learning mechanism requires the direct experience, and can not
be mediated. It does not necessarily require, however, the full phenomenological

7. The X Factor 21
consciousness of the individual, and therefore does not always represent the
typical experience.
The model-based system is more complex, and it allows different types of
learning. A direct experience is not always required in the learning and decision
making processes: cultural, mediated learning has an important role in both
semantic acquisition and models building. Its most important way of learning,
however, is trough direct, conscious experiences: they are by far the most impor-
tant sources of the internal representations. The schemas that are formed by
the generalization of recurrent experiences [8] are one of the models of internal
representation upon which the goal oriented behavior is based. Episodic details -
memorable experiences [3] - are another essential source for planning and deci-
sion making.
The model-based system uses all the three main ingredients of what we con-
sider experience.
1. The schemata and the scripts that arise from the process of generalization of
the experiences are at the basis of the internal representation of the model.
The schemata build upon recurrent experiences constitute the building blocks
for the model based reasoning.
2. The memorization of the most salient features and gestalts of an episode [3]
allow to represent the outliers of the schema, and to give phenomenological
color to the model. The specific episodic memories are necessary for:
– identify specific environmental patterns (special cases)
– estimate both the plausibility and the expected value of simulated scenar-
ios
– keeping track of the ongoing plans
3. The dialog between the executive functions, the episodic and the semantic
memory allows the system to generate the representation, identify the goal,
the plan, the tasks and actions, monitor the execution and the events, and
correct the action or adapt the plan.
4.1 The Role of Products and Services
People can have experiences without products and services. Technology, tools
and cooperative behaviors, however, are part of the material and non-material
culture that co-evolved with the humankind, shaping our environment, our genes
and our brain. Within the metaphor of planning as a journey towards a goal,
artifacts and services constitute bridges that enable a path, or make it more
convenient, easier, smoother, or pleasurable. In the evolutionary perspective,
artifacts and services are adaptations in the same definition we cited in the
previous paragraphs. The product-as-bridge can be seen as the basis of the design
as problem solving, and constitutes a proximate explanation [33]. The product-
as-adaptation constitutes an ultimate explanation, and is compatible with the
iterative view of design as a dialog.
Technology can have an important role in helping people to fulfill their goals
and satisfy their needs [20], and in the most recent drafts of the ISO 9241-11

8. 22 S. Bussolon
revision it is recognized that products, systems and services can help a person
to satisfy a wide range of goals [6]: output related outcomes, personal outcomes,
usability outcomes, and safety goals like security and privacy.
5 The Utility of the Definition
I felt the urge to identify a definition of experience when, as a teacher of a HCI
course, I attempted to explain what the user experience is. My feeling was that
the main differences between the many definitions of ux were attributable to dif-
ferent, implicit concepts of experience and that, therefore, an explicit definition
would have been a useful basis of explanation.
A second reason that motivated me to seek a founding definition was the
observation that my syllabus was a list of topics and methods without a system-
atic organization; the definition justify the study those topics as the building
blocks of experiences: the motivations, the definition of knowledge, the episodic
and semantic memory, the executive functions, and the mental models.
Third, this perspective can help students (and practitioners and stakeholders)
to resist the temptation to begin designing without a research phase. The expe-
rience perspective induces the designer to start a project by trying to identify
the needs, attitudes, internal schemes and mental models, to produce experience
maps and customer journeys, using tools and elicitation methods like interviews,
laddering, task analysis, experience journey mapping, free listing, triadic sorting,
and repertory grid.
Finally, it can have the strategic function to help an organization to find a
competitive advantage trough positioning.
In his classic What is strategy, Porter [30] defines strategy as competitive
advantage, that can be reached by strategic positioning or by improving the value
chain. There are three ways to acquire a competitive advantage: doing something
that is cheaper, or better, or different. Improvements in the value chain can
guarantee a cheaper or a better product. Strategic positioning is oriented at
creating a different product.
Studying the individuals’ experiences, their motivations, their attitudes helps
to identify unfulfilled needs, encouraging the exploration of spaces and opportu-
nities of strategic positioning.
The user experience design, with his emphasis on the usability and the experi-
ential components, can have a dramatic impact on the value chain of a product,
or system, or service. The combination of experience research and ux design
can become a central asset in the definition of the strategy and in reaching a
sustainable competitive advantage.
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